My Xbox 360 has worked with my HD television via HDMI for about 3 months until one day I could not play Xbox 360 via HDMI.
Troubleshooting the issue was my first resort.
First, I tested the HDMI cable I was using to play the Xbox and it was functioning properly between my laptop and tv.
Next, I tested the Xbox to my TV with another HDMI cable and it did not work.
Then, I tested the Xbox on another TV using the same HDMI cable and it connected.
Then I made sure that the display settings on my TV were functioning and tried connecting it again.
It did not work.
Finally I did my research and found out the Xbox was unable to only connect to one specific TV, the primary TV I use.
This was because of a handshake error between the Xbox 360 HDMI input and the TV's output. The handshake error lay in the edmi starter not functioning properly, kind of like a starter not working on an engine.
But the bizarre part is that it was only happening between the Xbox 360 and that specific TV. ??? So weird. I don't understand how electronic devices communicate but this was leading me to believe that there was some kind defect in the Xbox 360's HDMI functionality.
So finally, the way to resolve this issue: buy an HDMI switcher that connects the xbox to the TV.
On another issue, I think Xbox should provide people who are experiencing this some kind of more efficient instruction or rebate.
This event is not an isolated one.
Below is how I solved the issue
Last note and basically my whole point for this. Xbox support could not help me. If they provided this solution on their website, I could give them credit for helping, but no.